Paul:
There are a number of NY / NJ metro courses that could be considered.
Frankly, having such a category itemized on a frequent basis would be a good assignment for any of the major golf pubs to do.
Pat mentioned Montclair GC in West Orange, NJ and clearly the contributions of Donald Ross and Charles Banks are there for all to see. With the 250 foot elevation change from the top of the hill to the back of the property you have a number of really interesting and holes.
I also believe Morris County GC in Convent Station (Seth Raynor) is also quite good although clearly a notch behind Montclair. The long par-4 7th (named Big Ben) is very well done.
Atlantic City CC in Northfield is also another good choice. If memory serves -- I believe it's also under 6,500 yards and was recently restored / upgraded by Tom Doak.
I wish I could also mention Forsgate -- for a long time the course was barely over 6,500 yards but I believe with some extensions it's closer to 6,700 yards.
Clearly, one would have to include Somerset Hills in Bernardsville.
On the New York side I believe among recent designs one could possibly include C&C's Easthampton club. The updated efforrs by architect Stephen Kay at Seawane has also been well received and I believe it's right at the 6,500 cutoff.
I'm sure I can include a few others from The Empire State.